A new scientific study has determined that the combination of drugs used to kill prisoners under a sentence of death has not always worked correctly:

The drugs used to execute prisoners in the United States sometimes fail to work as planned, causing slow and painful deaths that probably violate constitutional bans on cruel and unusual punishment, a new medical review of dozens of executions concludes.

Even when administered properly, the three-drug lethal injection method appears to have caused some inmates to suffocate while they were conscious and unable to move, instead of having their hearts stopped while they were sedated, scientists said in a report published Monday by the online journal PLoS Medicine.

As I understand it, the Church has declared that capital punishment may be a legitimate means of protecting and securing the common good if no other practical means exists to do so. She recognizes therefore the right of legitimate governing authority to render prudential judgement in the matter, while upholding the foundational principal of respect for each and every human life. However, John Paul II has said that the current realities of society make the necessity of capital punishment exceedingly rare. Here is the section from the CCC:

2266 The State's effort to contain the spread of behaviors injurious to human rights and the fundamental rules of civil coexistence corresponds to the requirement of watching over the common good. Legitimate public authority has the right and duty to inflict penalties commensurate with the gravity of the crime. the primary scope of the penalty is to redress the disorder caused by the offense. When his punishment is voluntarily accepted by the offender, it takes on the value of expiation. Moreover, punishment, in addition to preserving public order and the safety of persons, has a medicinal scope: as far as possible it should contribute to the correction of the offender.

2267 The traditional teaching of the Church does not exclude, presupposing full ascertainment of the identity and responsibility of the offender, recourse to the death penalty, when this is the only practicable way to defend the lives of human beings effectively against the aggressor. If, instead, bloodless means are sufficient to defend against the aggressor and to protect the safety of persons, public authority should limit itself to such means, because they better correspond to the concrete conditions of the common good and are more in conformity to the dignity of the human person. Today, in fact, given the means at the State's disposal to effectively repress crime by rendering inoffensive the one who has committed it, without depriving him definitively of the possibility of redeeming himself, cases of absolute necessity for suppression of the offender 'today ... are very rare, if not practically non-existent.'[John Paul II, Evangelium vitae 56.]

Given the results of this study--and the fact that 11 states have suspended the use of lethal injection as a more humane method of capital punishment--what can Catholics bring to the further discussion of capital punishment that will inevitably result in the wake of this discovery? How can the riches of the Church's Teaching best be applied to this situation?